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EMIn telephony, an arrangement that uses separate leads, called the E lead and M lead, for signaling and supervisory purposes. The near end signals the far end by applying -48 VDC to the M lead, which results in a ground being applied to the far end`s E lead. The E originally stood for ear and the M originally stood for mouth. The analog E&M trunk interface in Telesis systems satisfies conditions for AT&T Type-V connection. The interface may individually be set to either a two- or four-wire interface by appropriate configuration of the on-the-board jumpers. Xymphony supports many different line and register signaling types over the E&M lines. An additional detector on the M-wire checks the DC feed on the line for faulty conditions at far-end equipment. The reference impedance is 600 ohm resistive. The interface can be programmed as incoming, outgoing, both-way trunk, or unavailable. Internal Links |